THE FUNGI 



269 



mushroom matures, the stipe elongates and the pileus expands, 

 so that the lamellae are lifted into the air and properly disposed 

 for the dissemination of the spores. At the same time the veil 

 is ruptured, and a remnant of it clings to the stipe as a ring of 

 tissue, called the annulus, marking the former junction of the 



Basidiiim 



Pileus 

 Lamella , 



Spores 



^..'Paraphysis 



FIG. 148. Spore formation in a mushroom, Coprinus 



a, vertical section of the mushroom fruit; b, vertical section of three lamellae, or 

 gills (the arrows indicate the path of the spores when shot off from the sterigmata) ; 

 c, d, portions of the hymenium showing spores on the basidia ; c, surface view of the 

 hymenium ; d, sectional view. Further discussion in the text, b, c, d, redrawn from 

 Buller's " Researches on Fungi " 



veil with the stipe. The output and dissemination of spores is 

 also greatly facilitated by the structure of the lamellae and by 

 the method of producing and freeing the spores by the specialized 

 spore-producing cells, or basidia. 



Asexual reproduction. The lamellae are formed by hyphae 

 which grow downward from the pileus and unite to form the 

 various layers of the gills. 



The central portion of a lamella is made up of vertically 

 arranged hyphae which unite by cross branches to form the 



